In air batteries (also referred to as metal-air batteries), a metal having high energy density can be used as a negative electrode active material, and oxygen in the air is used as a positive electrode active material. Thus, air batteries may operate as a half battery, and the amount of electrode active material may be reduced or halved. Accordingly, air batteries may theoretically obtain an improved energy density. The electromotive force and capacity of air batteries differ greatly depending on the kind of metal that is used for the negative electrode. For example, research has been conducted into practical applications of air batteries in which lithium (i.e., a metal with the smallest atomic number) is used for a negative electrode because a large capacity may be obtained, as well as improved theoretical electromotive force as large as approximately 3 V.
An air battery may include an air electrode (positive electrode), a negative electrode, an electrolyte layer, and a housing provided with an opening through which oxygen is taken in from the outside, for example. In certain embodiments, the air electrode is formed from a carbon material and a catalyst, such as a metal, that is added to the carbon material, in a reaction field of oxygen. As described above, the negative electrode may be formed from a metal element such as lithium. An electrolytic solution that is used for the electrolyte layer is broadly classified into an organic electrolytic solution and an aqueous electrolytic solution. Various electrolytic solutions have advantages and disadvantages. However, an organic electrolytic solution has the advantage that the theoretical capacity is larger than that of an aqueous electrolytic solution. In addition, the electrolyte layer may be formed from a separator impregnated with the electrolytic solution to prevent a short between the air electrode and the negative electrode.
In air batteries in the prior art, a metallic mesh for current collection is provided on an oxygen intake surface of the air electrode, and during charging and discharging, a voltage, which is positive with respect to the negative electrode, is applied to the metallic mesh.